PHYSICS: ThermodynamicsAP, AP Physics 2 - Thermodynamics

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Thermodynamics
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Terms in this set (57)
Thermodynamics
Flow of energy in the universe, as the flow relates to work, heat, entropy, and the different forms of energy
Zeroth law of thermodynamics
Objects are in thermal equilibrium when they are at the same temperature, transitive property in thermal systems (a=b, b=c, a=c)
Temperature
A physical property of matter that relates the average kinetic energy of the particles in a substance
Heat
The transfer of thermal energy from a hotter object(higher temp/energy) to a colder object (lower temp/energy)
Thermal equilibrium
No heat flows between two objects in thermal contact
Fahrenheit to Celsius equation
Image: Fahrenheit to Celsius equation
Kelvin to Celsius equation
Image: Kelvin to Celsius equation
Thermal expansion
delta L= change in length
alpha= coefficient of linear expansion
L= original length
delta T= change in temperature
Image: Thermal expansion
Isolated systems
System not capable of exchanging energy or matter with their surrounding; total change in internal energy is zero
e.g. bomb calorimeter
Closed systems
System capable of exchanging energy, but not matter, with the surrounding
e.g. gas in vessels with movable pistons
Open systemsSystems can exchange both matter and energy with the environment e.g. Boiling pot of waterState functionsThermodynamic properties that are a function of only the current equilibrium state of a system e.g. pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, entropyFirst law of thermodynamicsThe change in the total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system, minus the amount of energy transferred from the system in the form of workFirst law of thermodynamics equationdelta U= internal energy Q= heat W= workSecond law of thermodynamicsIn a closed system, energy will spontaneously and irreversibly go from being localized to being spread outThree means by which heat can transfer energyConduction, Convection, RadiationConductionDirect transfer of energy from molecule to molecule through molecular collisions e.g. metal pan to chicken, gases are poor conductorsConvectionTransfer of heat by the physical motion of a fluid over a material e.g. Fans circulate hot air inside ovenRadiationTransfer of energy by electromagnetic waves e.g. Sun keeps earth warmSpecific heat (c) of a substanceThe amount of heat energy required to raise one gram of a substance by one degree Celsius or one unit KelvinHeat gained or lost by an objectq= heat gained or lost by an object m= mass c= specific heat of substance delta T= change in tempHeat of transformationDuring a phase change, heat energy causes changes in PE and energy distribution, but not KE. No change in tempHeat of transformation equationq= amount of heat gained or lost from substance m= mass L= heat of transformationSpecific heat for liquid H2O4.184 J/g . KFour special types of thermodynamic systems in which a given variable is held constantIsothermal, Adiabatic, Isobaric, Isobaric, IsovolumetricIsothermal processT is constant, change in internal energy= 0Adiabatic processNo heat is exchangedIsobaric processP is constantIsovolumetric (isochoric) processV is constant, work done on or by system = 0EntropyMeasure of how much energy has spread out or how spread out energy has becomeEntropy and heatdelta S= change in entorpy Q rev= heat gained or lost in reversible process T= temperatureEntropy of universeThis total entropy of the universe is always increasinginternal energythe energy in a system arising from the relative positions and interactions of its parts.entropylack of order or predictability; gradual decline into disorder. // a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.plasmaan ionized gas consisting of positive ions and free electrons in proportions resulting in more or less no overall electric charge, typically at low pressures (as in the upper atmosphere and in fluorescent lamps) or at very high temperatures (as in stars and nuclear fusion reactors).conductionthe process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.convectionthe movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in the transfer of heat.radiationthe emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization.thermodynamicsa branch of physics concerned with heat and temperature and their relation to energy and work. It defines macroscopic variables, such as internal energy, entropy, and pressure, that partly describe a body of matter or radiation.isochorica thermodynamic process during which the volume of the closed system undergoing such a process remains constant.adiabaticrelating to or denoting a process or condition in which heat does not enter or leave the system concerned.isothermala change of a system, in which the temperature remains constantheat enginea device for producing motive power from heat, such as a gasoline engine or steam engine.heata form of energy associated with the movement of atoms and molecules in any material.Carnot enginemost efficient heat engine, uses two isothermal and two adiabatic processesCarnot cyclean ideal reversible closed thermodynamic cycle; back to it's original stateabsolute zerothe lowest temperature that is theoretically possible, at which the motion of particles that constitutes heat would be minimal.molethe SI unit of amount of substance, equal to the quantity containing as many elementary units as there are atoms in 0.012 kg of carbon-12.sublimationa transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phasedepositionwhen an object goes from a gas straight to solid, without going through a liquid phasespecific heatthe heat required to raise the temperature of the unit mass of a given substance by a given amountcaloriethe energy needed to raise the temperature of 1 kilogram of water through 1 °C, equal to one thousand small calories and often used to measure the energy value of foods.ideal gasa hypothetical gas whose molecules occupy negligible space and have no interaction and that consequently obeys the gas laws exactly.work done on a system(+)work done by system(-)isobaricconstant pressurelatent heat (transformation, fusion, vaporization)the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without change of temperature